//===================================================================================
// Microsoft patterns & practices
// Composite Application Guidance for Windows Presentation Foundation and Silverlight
//===================================================================================
// Copyright (c) Microsoft Corporation.  All rights reserved.
// THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY
// OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT
// LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
// FITNESS FOR A PARTICULAR PURPOSE.
//===================================================================================
// The example companies, organizations, products, domain names,
// e-mail addresses, logos, people, places, and events depicted
// herein are fictitious.  No association with any real company,
// organization, product, domain name, email address, logo, person,
// places, or events is intended or should be inferred.
//===================================================================================
using System;
using Microsoft.Practices.ServiceLocation;

namespace Microsoft.Practices.Prism
{
	/// <summary>
	/// Defines extension methods for the <see cref="ServiceLocator"/> class.
	/// </summary>
	public static class ServiceLocatorExtensions
	{
		/// <summary>
		/// Attempts to resolve specified type from the underlying <see cref="IServiceLocator"/>.
		/// </summary>
		/// <remarks>
		/// This will return null on any <see cref="ActivationException"/>.</remarks>
		/// <param name="locator">Locator to use in resolving.</param>
		/// <param name="type">Type to resolve.</param>
		/// <returns>T or null</returns>
		/// <exception cref="ArgumentNullException">Thrown when <paramref name="locator"/> is <see langword="null"/>.</exception>
		public static object TryResolve(this IServiceLocator locator, Type type)
		{
			if (locator == null) throw new ArgumentNullException("locator");

			try
			{
				return locator.GetInstance(type);
			}
			catch (ActivationException)
			{
				return null;
			}
		}

		/// <summary>
		/// Attempts to resolve specified type from the underlying <see cref="IServiceLocator"/>.
		/// </summary>
		/// <remarks>
		/// This will return null on any <see cref="ActivationException"/>.</remarks>
		/// <typeparam name="T">Type to resolve.</typeparam>
		/// <param name="locator">Locator to use in resolving.</param>
		/// <returns>T or null</returns>
		[System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Design", "CA1004:GenericMethodsShouldProvideTypeParameter")]
		public static T TryResolve<T>(this IServiceLocator locator) where T : class
		{
			return locator.TryResolve(typeof(T)) as T;
		}
	}
}